The Truth about Dirt

A couple of weeks ago I had the pleasure of meeting and hunting fossils with a geological engineer in the mountains of Montana. Besides wearing me out on the hike (He is ten years my senior.), we had a vigorous and extended conversation about the geological record. In the process, I asked him a question that I have never heard anyone else ask, and for which I have never gotten a satisfactory long-age answer: The conversation went something like this: He was pointing and speaking of the earth layers around us, and I asked, "Where did the dirt come from?" He didn’t know what I meant, so I pointed out, "There are layers of fossils one on top of another. Once the lower layer was laid down, where did the dirt come from for the subsequent layers?" He went into an extended explanation of tectonic plate movement and subduction. (This is a good example of an argument fallacy called Ignoratio elenchi.) I replied, "I have no problem with the idea that earth’s plates move or that one may move underneath or on top of another, but I’m talking about sedimentary layers. If approximately 70-75% of our land surfaces are covered with sedimentary rock and dirt, the second, and all subsequent layers, could not possibly come from the remaining 25-30% of surface." He explained the lifting and erosion cycle, and that some mountains of the world are documented as still getting higher.  "Yes, I agree that uplift and erosion take place today simultaneously, and that some land is rising. But my question is, why are trilobites in the bottom layers and dinosaurs are buried on top of them? The dinosaur dirt must have been laid down from the top onto the trilobite dirt, not from the bottom up. If one layer was laid down, and then millions of years later another layer was laid down without disturbing the dirt already in place, where did the new dirt come from–and the layer on top of that and on top of that?" Our conversation extended through the hour decent on gravel roads, but I eventually allowed him to change the subject without a satisfactory answer. His last answer was, "It came from the sides." This of course ignores the observation, that there are no "sides." To date the only explanation that makes since to me is that all the dirt must all have been in suspension at the same time and gradually settled apart, perhaps taking weeks or months, not millions of years. If any reader of this site has a millions-of-years explanation to offer for where the dirt came from, please offer it. Thanks.

This entry was posted on October 23, 2007 at 11:49 am and is filed under Science and faith, Personal story. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or trackback from your own site.